Effect of disability, homelessness, and neighborhood marginalization on risk adjustment for hospital performance measurement

It is not known how disability, homelessness, or neighborhood marginalization influence risk-adjusted hospital performance measurement in a universal health care system. In this study, we evaluated the effect of including these equity-related factors in risk-adjustment models for in-hospital mortality, and 7- and 30-day readmission in 28 hospitals in Ontario, Canada. We compared risk adjustment with commonly used clinical factors to models that also included homelessness, disability, and neighborhood indices of marginalization. We evaluated models using historical data using internal-external cross-validation. We calculated risk-standardized outcome rates for each hospital in a recent reporting period using mixed-effects logistic regression. The cohort included 544 805 admissions. Adjustment for disability, homelessness, and neighborhood marginalization had little impact on discrimination or calibration of risk-adjustment models. However, the adjustment influenced comparative hospital performance on risk-standardized 30-day readmission rates, resulting in 5 hospitals being reclassified among below-average, average, and above-average groups. No hospital was reclassified for mortality and 7-day readmission. In a system with universally insured hospital services, adjustment for disability, homelessness, and neighborhood marginalization influenced estimates of hospital performance for 30-day readmission but not 7-day readmission or in-hospital mortality. These findings can inform researchers and policymakers as they consider when to adjust for these factors in hospital performance measurement.